The major objective of the Specialized Assay Core is to create greater efficiency by providing radioimmunoassays (RIAs), enzyme-linked immnosorbent assays (ELISA), immunogenetic assays, and other basic biochemical assays to support human and animal studies performed by individual DERC investigators at the Joslin Diabetes Center and some external users who are funded by the NIH and who do not have access to Core Facilities. Over the last 5 years, there have been several changes both in the scope of research and the number of rodent mouse models created to study various aspects of type 1 and type 2 diabetes, obesity, their complications, and a wide variety of human studies. At Joslin more than 110 rodent models have been studied over the past few years and 23 more are in various stages of being created, thereby increasing a need for measurement of rodent hormones and metabolites and setting up additional assays on a large scale. The Core allows more economic use of expensive or limited materials, provides for training of junior investigators, fosters interactions among research fellows and provides a basis for generating collaborative studies between institutions.